The objective of this core is to enhance scientific exchange between the Peru ICIDR Program projects and visiting investigators working in the area of tropical disease research. The core is also designed to provide investigators opportunities for research experience in the area of new and emerging gastrointestinal pathogens. Included in this Program project are the following organisms new viral agents (astro, calci, norwalk and new serotypes of rotavirus), and Cyclospora cayetanensis, a newly described protozoal parasite in association with diarrheal (illness) in children and adults, and Taenia solium. Two investigators per year will be chosen from applications solicited through paid advertisements in Science; letters to Medical Schools that have strong emphases in topical disease research and through bulletin board flyers at the annual November ASTM&H meeting. Application packets will contain salary, per diem, and travel information; also forms requesting information on educational background, research activities, and references. Additionally, each applicant will be asked to describe, in a one page statement, his/her interest in spending three months in Peru working with ICIDR personnel. This information will be reviewed by the four project leaders, and the ICIDR Director [Gilman] and Dr. Bob Black, Co-CL Core A. All nominations will then be forwarded for final review by the NIAID Program Officer and Scientific Coordinator.